I recently received my hardcopy of the PbtA RPG The Great American Novel and I’m not sure what I think about it. Note that this is all after a single read of the rules and no play experience, so it’s very much a set of first impressions.
On the one hand, it’s polished to a very tight focus: It’s about literary novel characters, how they change, and whether they rise to their heroic destiny or fall to a tragic end; it has very tightly defined characters (three stats, no playbook specific moves) that nevertheless capture their archetypes very well; and the mechanics are generally very limited, where basically the GM sets up conflicts (which are defined purely fictionally; there are no clocks or anything like that, as a conflict is either resolved or not) and the players act to resolve them.
All of that is very positive. I’m glad there’s no rules for harm or the like since it’s outside the relevant scope of the game.
On the other hand there seems to be very little tension for the players. The characters change in two main ways: by gaining new motivations and by their Arc value changing. The former is completely under their own control, and the latter, which seems like it should be what you’re pushing off against seems a bit… wishy-washy? Yes, you may start to rise or spiral down, but at any point you can spend a plot point (the game’s only currency) to switch to the other side - if you were rising you start to fall and vice versa.
While this gives the players a lot of control, it also… gives the players a lot of control. While there is obviously uncertainty in how the story will turn out, there seems to be very little uncertainty for the player as to the final destiny of their character if they desire to go in a particular direction. Again, this is after only reading the rules so this may be very different in actual play. (I’m also not that fond of giving a stat bonus to characters who are rising and a penalty to characters who are falling. I’m not sure what purpose that serves.)
I do find this falling/rising Arc to be highly interesting and something I would look at closely to incorporate into other games. It’s a more interesting way to have a character conclude their story than to die or retire to safety after a certain number of advancements IMO. It also reminds me of the positive/negative baggage mechanism from the Android boardgame, which was easily the best part of that game and something I wish had been picked up by other story-focused designs.
Anyway, it looks very intriguing and I look forward to someone explaining to me why I’m wrong about it. 
I’ll also note that it’s the first RPG in a very long time, perhaps ever, that have made me interested in playing completely ordinary characters in a naturalistic fashion so I guess that’s something.